Spatially resolved high-resolution x-ray spectroscopy of high-current plasma-focus discharges

Abstract

Soft x-ray emission from a Mather-type plasma-focus device (PF-1000) operated at ∼400 kJ was measured. The high density and temperature plasma were generated by the discharge in the deuterium-argon gas mixture in the modified (high-current) plasma-focus configuration. A spherically bent mica crystal spectrograph viewing the axial output of the pinch region was used to measure the x-ray spectra. Spatially resolved spectra including the characteristic x-ray lines of highly ionized Ar and continua were recorded by means of an x-ray film. The x-ray emission of PF-1000 device was studied at different areas of the pinch.

The K X-ray line structures for a warm dense copper plasma

“…The dotted line draped over the sticks is the sum of all these Lorentzians, with the widths defined by the code's transition frequency as computed by the code. For easier comparison with the experiment of Zajac et al [13] below, the solid line will be a convolution of this theoretical spectrum with the Gaussian instrumental response having a width of 5.0 eV.…”

“…[14]; another example is a Cu spectrum in Fig. 1, obtained serendipitously on the PF-1000 device [13]. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 …”

“…[13], but even if this spectrum were suppressed and Fig. 1 would only contain the harder copper Ka radiation, information about the plasma could still be derived from the structure and energy of these lines.…”

“…One example for which this could be done is a series of highresolution X-ray spectra obtained by Zajac et al [13] at the Plasma Focus (PF) on the~1 MA PF-1000 device at the Institute of Plasma Physics and Laser Microfusion (IPPLM) in Warsaw. The spatially resolved and time integrated X-ray spectra in the photon energy range of 210 keV were measured by means of the X-ray 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 focusing crystal spectrometer with spatial resolution in axial direction based on spherically bent crystal.…”

“…3 and Fig. 2 can be very useful in refining the interpretation of the copper K-line spectra highlighted here [13,14].…”